White solid activation

A white solid, m.p. 178 C. Primarily of interest as a brominaling agent which will replace activated hydrogen atoms in benzylic or allylic positions, and also those on a carbon atom a to a carbonyl group. Activating influences can produce nuclear substitution in a benzene ring and certain heterocyclic compounds also used in the oxidation of secondary alcohols to ketones. 

The crude ketone is chromatographed on acid-washed alumina (600 g, activity II). Elution with hexane-ether (4 1) gives a white solid (8.5 g) as the major fraction mp 77-82°. Recrystallization from methanol gives A-homo-5a-cholestan-4-one (3b 5.77 g 41% yield) mp 86-88° ... 

The mixture is refluxed with stirring for ten hours, cooled and filtered. The filtrate is extracted three timas with 200 cc portions of 6 N acetic acid. The aqueous acetic acid solution is then made strongly basic with 10% sodium hydroxide solution, and extracted three times with 200 cc portions of ether. The ether extract is dried with anhydrous sodium sulfate, stirred with 5 g of activated carbon and filtered to provide 2-[p-chloro-a(2-di-methylaminoethoxylbenzyll pyridine in solution. Addition of a solution of 116 g (1 mol) of maleic acid in 1,500 cc of ether gives 323 g (79%) of solid which, on recrystallization from ethyl acetate, gives white solid 2-[p-chloro-a(2-dimethvlaminoethoxv)benzyl] pyridine maleate melting at 117° to 119°C. 

The highest fixed nitrogen-containing fertilizer 46.7 wt %, urea is a white solid that is soluble in water and alcohol. It is usually sold in the form of crystals, prills, flakes, or granules. Urea is an active compound that reacts with many reagents. It forms adducts and clathrates with many... 

While performing these reactions, the formation of a white solid that was recovered by filtration and identified by X-ray diffraction (XRD) analysis as BiOCl was observed. Thus, BiCl3 can be recovered at the end of the reaction and reused as BiOCl, which is also active under these reaction conditions, or reconverted... 

True alkaloids derive from amino acid and they share a heterocyclic ring with nitrogen. These alkaloids are highly reactive substances with biological activity even in low doses. All true alkaloids have a bitter taste and appear as a white solid, with the exception of nicotine which has a brown liquid. True alkaloids form water-soluble salts. Moreover, most of them are well-defined crystalline substances which unite with acids to form salts. True alkaloids may occur in plants (1) in the free state, (2) as salts and (3) as N-oxides. These alkaloids occur in a limited number of species and families, and are those compounds in which decarboxylated amino acids are condensed with a non-nitrogenous structural moiety. The primary precursors of true alkaloids are such amino acids as L-ornithine, L-lysine, L-phenylalanine/L-tyrosine, L-tryptophan and L-histidine . Examples of true alkaloids include such biologically active alkaloids as cocaine, quinine, dopamine, morphine and usambarensine (Figure 4). A fuller list of examples appears in Table 1. 

A soln of Boc-Phe-NCA (0.58g, 2.0mmol) in THF (6.0mL) was stirred at 20°C and TEA (0.42mL, 3.0 mmol) was added. An aliquot of the mixture was immediately removed and placed in a 1.00-dm polarimeter cell. The total optical activity of the mixture at the sodium D line (589 nm) was monitored over time. After 90 min, the solvent was removed under reduced pressure from the remainder of the mixture to give a white solid. H NMR analysis of this material showed it to be pure Boc-Phe-NCA, unchanged from starting material except for its optical activity. The material exhibited [a]D20 +17 (c 1.1, THF), a loss of 86% of the original value for Boc-L-Phe-NCA of [a]D20 +119 (c 1.1, TFIF). 

CA is a yellow-white solid, with a molecular weight of 195.97, a melting point of 25°C, a boiling point of 22S°C and the odor of sour fruit. Sim described its activity as immediate in onset and causing eye and respiratory irritation. Rapid recovery (2-10 min) from its effects is produced by moving to fresh air. It is low in skin irritancy.93... 

Such a process would have an intensity exponent of unity as observed. A further fact in support of the disproportionation mechanism is that the yield of CF2CI2 is largely independent of the ketone pressure at room temperature an abstraction mechanism would require a first-order dependence upon ketone pressure. While the dimer of CF2, tetrafluoro-ethylene, has never been observed in the reaction mixture, a white solid collected in the cell which was probably a polymer of CF2. While the experimental conditions are not strictly comparable, it is significant that the absorption spectrum of CF2 has been observed in the flash photolysis of 1,3-dichlorotetrafluoroacetone.39 When the temperature is raised, however, the yield of CF2C12 in normal photolysis, increases rapidly suggesting an energy of activation and this process can only be chlorine abstraction. The rate function ... 

The peroxo complexes are white solids, soluble in mineral acids, but insoluble in common organic solvents. They are relatively stable at room temperature however, they lose active oxygen at elevated temperatures. Several of the compounds in Table 8 were isolated with... 

The pentoxides of vanadium, niobium, and tantalum react with hydrogen peroxide to produce per-acids of the general formula HR04. H20. These per-acids increase in stability with increase in atomic weight. Pertantalic acid is a white solid which can be heated to 100° C. without undergoing decomposition. The oxyfluorides of these metals also take up active oxygen to yield peroxyfluorides, which are much better defined in the case of niobium and tantalum than with vanadium. 

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